[Adverse effects and recovery after total intravenous anesthesia in children].

INTRODUCTION: Propofol has proven to be a reliable anaesthetic that can be used for both induction and maintenance purposes in most common surgical procedures, either in standard anaesthetic practice or as part of total intravenous anaesthesia (TIVA).

MATERIAL AND METHODS: Twenty healthy (ASAI) paediatric patients scheduled for elective minor abdominal or urology surgery were studied. Patients aged 7-16 years, weighing 25-64 kg, were premedicated with midazolam 0.1mg/kg and atropine 0.01mg/kg intramuscularly, 30 minutes before surgery. Induction dose of propofol for all patients was 2.5 mg/kg. Anaesthesia was maintained with an infusion of propofol 10 to 15 mg/kg/h. Fentanyl was injected 1-2 micrograms/kg 1 minute before the start of the infusion of propofol, just before the surgery and during the surgery if necessary. Pulse, blood pressure, respiratory rate, tidal volume, ETCO2, and O2 saturation were continuously recorded before, during and after the anaesthesia. Recovery scores were assessed with the Steward scoring system 3, 5, 15, 30, after the end of anaesthetic infusion. Blood was sampled 2 and 15 minutes after the induction, 5, 15 and 30 minutes after the end of propofol infusion.

RESULTS: There were no significant differences in age, weight, sort and length of the operations. After the induction spontaneous movements were registered in 35% of the patients, apnea in 25% and decrease in blood pressure in all patients. Maintenance was generally uneventful and there were no excitatory or other adverse effects. Blood concentration of propofol was followed during the anaesthesia and recovery period. Blood propofol concentration at which responses to surgery were not present were from 3.4 micrograms/ml to 4.5 micrograms/ml. Recovery was rapid and complete. All patients reached maximum value of Steward scoring system within the first 15 minutes. In the moment when patients open to command (7.2 +/- 3.2 min) average blood concentration was 1.9 micrograms/ml and when they were orientated (13.1 +/- 2.1 min) 1.3 micrograms/ml. Postoperative nausea and vomiting were not registered.

DISCUSSION: This study shows that propofol provides satisfactory, stabile anaesthesia for children with rapid and complete recovery. Children may need larger doses of propofol for induction and maintenance of anaesthesia. Results from literature suggest that propofol is metabolised faster in children than in adults (9). The incidence of side effects was low. Large vein of the forearm or antecubital fossa were used for injection of propofol and there was no pain during administration the drug. Induction dose was given slowly (over 40 seconds) and apnea was relatively rare (25%). Decreases in arterial pressures from baseline levels are known to occur with propofol but in this study it was less than in others. We find a relatively high incidence of spontaneous movements during induction (35%). Nausea and vomiting were not recorded. A continuous infusion of propofol, as described here, effectively produced stable anaesthesia without use of inhalation agents. It must be remembered that propofol possesses only hypnotic properties and additional analgesia is necessary, fentanyl is a satisfactory agent in this respect. We found that average blood propofol levels of 3.5 +/- 0.9 micrograms/ml were necessary to prevent autonomic responses during this sort of surgery. Suggested hypnotic blood levels of propofol in literature are from 2.5 to 6 micrograms/ml (5). The usual endpoints of anaesthesia (eye opening and orientation) have been measured by several authors and found to occur at concentrations of the ranges of 1.0 to 2.9 micrograms/ml and 0.6 to 1.8 g/ml, respectively.

CONCLUSION: Due to greater ease of control in regard to anesthetic depth and more rapid recovery, propofol is superior to other intravenous hypnotics for maintenance of anaesthesia.